Participants will be sequentially enrolled into four cohorts and randomly assigned to receive either RMD or placebo. The cohorts will differ in the dose of RMD given. Participants in Cohorts 1, 2, and 3 will have one intravenous (IV) infusion of RMD or placebo at Day 0. Participants in Cohort 4 will have four IV infusions of RMD or placebo at Days 0, 14, 28, and 42.